Optical films, such as cellulose acylate films, are used for various liquid crystal displays, as optical elements of liquid crystal displays, for example, supports for optical compensation films, and protective films for polarizing plates.
In addition to an indoor use of the liquid crystal display, such as a TV use, a chance of the outdoor use thereof is increased, for example, use as a mobile device. As a result, development of a liquid crystal display is required, which is impervious to the use under the conditions of higher temperature and higher humidity than ever before.
Further, a demand for the liquid crystal display to be impervious to more various uses even under unforgiving conditions is growing, and durability at a higher level than ever before has been required from year to year.
In addition, the liquid crystal display has been increased in size and decreased in thickness mainly in TV applications in recent years, and thus the optical film of a constitutional member is also required to be thinned in accordance therewith. An appropriate hardness and favorable cutting property have been considered to be important for the optical film from the viewpoint of workability as well, and the thinned optical film is further required to be improved in the hardness and cutting property.
In the optical film using a cellulose acylate film, it is known that a specific compound is contained in the film, for further improvement in the performance, or in order to solve various problems in the properties as an optical film or the production thereof.
For example, it is proposed an organic acid compound with pKa of 2 to 7 (see Patent Literature 1), in order to suppress the fluctuation of the retardation of the optical film due to the environmental humidity.
On the other hand, in a silver halide photographic light-sensitive material which is a color negative film rather than the optical film, it is proposed to use a particular hydroxyamine compound, in order to improve storability of the latent image ranging from after photographing to development (for example, see Patent Literature 2). However, a working latent image of the silver halide does not exist in the optical film.